Vampire Knight tells the story of Yuki Cross. The earliest thing she remembers is being attacked on a snowy night by a vampire, and being rescued by Kaname Kuran, who is also a vampire.
The story takes place 10 years after that event, Yuki is now the adopted daughter of the Headmaster of Cross Academy. She and her longtime friend Zero Kiryu keep peace at the academy, making sure no problems arise between the Day Class (humans) and the Night Class (vampires).
However, the peace they try to keep is fragile, and personal feelings begin to interrupt their duty.